Dual safe fuze with spring preloader

#The U.S. Army presently employs a mine clearing system (USMCS) for providing a cleared path in a battlefield. The system comprises a mine clearing line charge (MICLIC), which is dispensed at the battle zone by a rocket attached to its front end and has attached to its rear end a fuze and an arresting cable, which in turn is anchored to a trailer containing the line charge and other system components. At the conclusion of the rocket trajectory, the rocket, line charge, fuze and cable are stretched out in a long line on the ground, and the fuze has been armed by the pull of the launcher cable on the arming pin so that the high explosives in the line charge can be initiated by detonators in the fuze assembly.

#The current M1134 fuze employed in the MICLIC system is a single safe fuze, wherein the only safety is an arming pin, which holds the spring loaded rotor out of line. This pin is retracted when it is pulled by an arresting cable of the line charge, thereby fully arming the fuze.

#The current M1134 fuze does not meet present military standards for fuze design safety criteria because it lacks safety redundancy, has no fail-safe feature and requires stored rotor spring energy to arm. In view of these safety deficiencies the current M1134 fuze is approved for use with the MICLIC only for field assembly to the line charge. Storage of the MICLIC with the fuze assembled is not permitted.

#FIG. 1 is an exploded view of the present M-1134 fuze.

#FIGS. 2 and 2A show a partial cutaway view of the present M-1134 fuze.

#FIG. 3 shows an end plan view of internal parts of the present M-1134 fuze.

#After the MICLIC trailer is positioned, the rocket launcher is raised and the shorting switch is closed, the operator rotates a firing control switch to the "ROCKET" position and repeatedly squeezes a 50 cap blasting machine (not shown). An electrical pulse is thereby transmitted through the special purpose electric cable via the launcher safety switch assembly and the rocket motor connector to ignite the rocket motor propellant, whereby the rocket propels the linear demolition charge across the selected area. As the last 10 feet of the arresting cable leaves the charge container, the lanyard attached to the charge container safety switch arm pulls the arm up and closes the electrical circuit so that the linear detonation charge can be initiated. When the rocket is in flight, the cable stretches, causing the arming wire to pull the arming pin assembly in the fuze. The tension in the wire withdraws the arming pin from the rotor, which releases the rotor to rotate by spring action to the armed position, thereby aligning its lead charges with the electric detonators and the booster charges. When the arming pin is pulled, the short across the two detonators is opened and the arming circuit is closed.

#After the line charge is deployed on the ground, the operator rotates the firing control switch indicator to the "CHARGE" position (not shown) and repeatedly squeezes the handles of the 50 cap blasting machine, whereby an electrical pulse is transmitted through the special purpose electrical cable, the launcher safety switch assembly, the electrical lead, the arresting cable fuze connector and the fuze. On reaching the fuze, the pulse detonates the electrical detonators, which in turn detonate the leads in the rotor, the boosters in the disk and the penaerythritol tetranitrate (PETN) relays in the demolition charge fuze connector. Initiation of the PETN relays detonates the strands of the PETN detonating cord, which causes high order detonation of the composition C4 pellets in the linear demolition charge.

#The present M1134 fuze is shown in FIGS. 1, 2 and 2A comprises a center tube enclosed in a crimped-on container, which is closed at the front end by a thin aluminum wall. The center tube contains a threaded portion, which is secured to the wall end of the container by a circular nut, and an externally threaded portion, which is threaded into the open end of the container, and also contains two slots for meshing the demolition charge connector with the fuze. The fuze is sealed against the entrance of moisture with two O-rings.